000
FXUS63 KEAX 011132
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
632 AM CDT SAT AUG 1 2015
.DISCUSSION...
Issued at 417 AM CDT SAT AUG 1 2015
Today - Sunday:
Good ole northwest flow. Can`t let your guard down even when there
are no discernible fronts nearby as weak/nebulous embedded
perturbations can and do wreak havoc with dry forecasts. Early this
morning weak isentropic ascent on the 305K and 310K surfaces appear
to be the main drivers for convection today through Sunday. Friday
night activity which formed over eastern NE via this process
dissipated as it moved into northern MO. However, satellite and
regional radar composites show a narrow band of ac/scattered
convection has formed from southwest SD through central NE. This
activity could persist through the morning hours and possibly slide
into northwest MO by late morning/early afternoon. Short range and
operational models not really picking up on this but feel enough of
a concern to warrant slight chance PoPs for this afternoon.
Later this evening more robust convection is expected to form
further north in response to a stronger shortwave and development of
the low-level jet. While the initial activity will likely form north
of the CWA the mid level steering flow and cold pool outflow could
easily send convection spreading into north central and northeast MO
later this evening. The severe threat will depend on the arrival
time as the instability will be decreasing by early evening. The 0-
6km shear averaging 30kt through late evening will be
sufficient to support at least an isolated severe threat.
A shortwave trough dropping southeast from central Canada through
the western Great Lakes on Sunday will push a cold front southward
and towards northern MO. Low level convergence of pooled moisture
ahead of the front plus moderate instability should be sufficient to
support at least widely scattered convection along the front and
enough to justify PoPs over northern MO Sunday afternoon. Otherwise,
typical mid summer heat and humidity should result in heat indices
from 95-100.
Sunday night - Monday:
The cold front will likely stall over the CWA Sunday night before
lifting back north on Monday. Not overly excited by the lift and
upper support so PoPs are limited to mainly slight chance variety.
One more uncomfortable day before we see an extended reprieve from
the heat.
Tuesday - Friday:
An unsettled period with several chances for convection as well as
below average temperatures. Operational models are in pretty good
agreement with a notable shortwave trough rolling eastward from the
intermountain region through the Central Rockies and Central Plains
and in effect flattening the upper high. Some differences in timing
and placement of the shortwave, enough to keep PoPs in the chance
category Tuesday through Wednesday.
The upper ridge temporarily reasserts itself by mid week with
heights building northward through the Front Range before another
shortwave tops the ridge axis and slides southeast towards the CWA.
In turn this will generate another round of convection. Being this
far out and not overly confident on timing it`s best to play this
with 30-40% PoPs.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday Morning)
Issued at 628 AM CDT SAT AUG 1 2015
VFR conditions will persist with light south to southwest winds.
Narrow band of convection over eastern NE expected to slide south and
remain west of the MO/KS border with high level debris cloudiness
spreading across northwest and west central MO. Later this evening
through the overnight hours there will be a chance for showers and
storms over parts of north central and northeast MO.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
DISCUSSION...MJ
AVIATION...MJ